All The World's Primates

Survey of the Habitat of Rare Bolivian Monkeys Aids the Establishment of a Municipal Reserve

June 01, 2011

Heidy Lopez-Strauss and Jesus Martinez at a school teaching
a class about environmental conservation.
(Photo by WCS)

Jesus Martinez, Heidy Lopez-Strauss and Robert
Wallace

Between 2004 and 2010, with funding from PCI and the Wildlife Conservation
Society, we documented the distribution of the two titi monkeys(Callicebus) in the central and western parts of the Beni
Department in Bolivia. Living only in Bolivia, these titis both have extremely restricted ranges. The information was provided to local
authorities, helping to establish a
Municipal Reserve in the Santa Rosa del Yacuma Municipality. This important conservation initiative protects both titi
monkeys, encompassing the majority of their distribution.

Olalla Brothers’ titi (Callicebus olallae) has the most
restricted distribution, limited to the southwestern part of Beni
Department with a range of only 5000 hectares. Beni titi monkey (C. modestus) has a slightly larger distribution with an occupancy
area of 45,000 hectares. Several research projects have been simultaneously conducted, to learn about diet, demography and population
abundance of both species. We determined that C. olallae forms groups of on average two individuals, and we estimate that the maximum
population is only 1,927 individuals. For C. modestus each group is formed by an average of 2.64 individuals, with a maximum number
of 20,072 individuals. Diet and behavior studies are currently being analyzed for publication in 2012. With the information gathered, we had
enough evidence to determine the IUCN threat category of “Endangered” for both species.

The challenges we face now are 1) to provide help with the development of a management plan for the reserve,
and the extent of the main threats facing the monkeys 2) to learn how the species are responding to increasing threats in the region and
establish environmental monitoring programs, and 3) to develop locally appropriate outreach and environmental education activities. Current
support from PCI is allowing us to assess the historical and current deforestation, and begin to plan appropriate conservation actions
including coordination with the Bolivian road authorities which are planning a new road in the middle of the ranges of the titis.